1. Field of the Invention
The present invention generally relates to a rotary connector to be used as a means for electrically connecting electrical components, such as an airbag inflator mounted on a steering wheel, to a car-body-side circuit. More particularly, the present invention relates to a rotary connector supported by a combination switch whose stator member has a canceling mechanism for a winker.
2. Description of the Related Art
A rotary connector is incorporated into a steering device of a car and is used as an electrical connection means for electrically connecting a steering wheel to a steering column. In such a case, the rotary connector broadly employs a mounting structure in which a rotor member thereof is connected to the steering wheel and in which a stator member thereof is attached to a combination switch that is fitted to the steering column.
FIG. 3 is a sectional diagram showing a conventional rotary connector. This rotary connector 1 broadly comprises a stator member 2, a rotor member 3, a slip-off preventing member 4 for rotatably connecting the rotor member 3 to the stator member 2, and a flexible cable 5 accommodated in an annular space provided between the stator member 2 and the rotor member 3. The stator member 2 consists of a cylindrical outer peripheral wall 2a and a ring-like bottom plate 2b. The outer peripheral wall 2a and the bottom plate 2b are integrated into one piece by being screwed or thermally caulked. The rotor member 3 has a cylindrical inner peripheral wall 3a and a ceiling plate 3b. A driving pin 3c is provided on the top surface of the ceiling plate 3b in such a way as to project therefrom. The slip-off preventing member 4 has a cylindrical portion 4a and a flange portion 4b. A cancel cam 4c is formed outside the lower part of the cylindrical portion 4a. The cylindrical portion 4a of the slip-off preventing member 4 is inserted from below into the space surrounded by the inner peripheral surface wall 3a of the rotor member 3 fitted to the upper opening of the stator member 2. Then, the cylindrical portion 4a and the rotor member 3 are snap-connected to each other. Thus, the rotor member 3 and the slip-off preventing member 4 are rotatably connected to the stator member 2 in such a manner as to be integral with each other. The flexible cable 5 is constituted by a flat cable having a plurality of conductors carried by belt-like insulating tape. Both the ends of this flexible cable 5 are respectively fixed to the outer peripheral wall 2a of the stator member 2 and the inner peripheral wall 3a of the rotor member 3 and are electrically led to the exterior.
On the other hand, a center hole 8 is provided in a casing 7 constituting an outer shell of the combination switch 6. This casing 7 is mounted on a column cover (not shown) of the steering device. An operation lever 9 for performing a winker operation and a passing operation is rotatably supported on the combination switch 6. The combination switch 6 incorporates a locking mechanism for locking this operation lever 9 in an operating position and a canceling mechanism for a winker. The canceling mechanism is operative to automatically return the operation lever 9, which is in the operating position, to a center position. A leading edge of a canceling lever 10, which is a constituent component of the canceling mechanism for a winker, projects into the center hole 8. Incidentally, a wiper switch (not shown) is attached through the center hole 8 to a place being opposite to the operation lever 9.
The stator member 2 of the rotary connector 1 constructed as described above is fixed to the top surface of the casing 7 of the combination switch 6 by being screwed or snap-connected. At that time, the cylindrical portion 4a of the slip-off preventing member 4 projecting downwardly from the stator member 2 is inserted into the center hole 8 of the combination switch 6. A leading edge of the canceling lever 10 of the canceling mechanism for a winker is placed in a turning region of the cancel cam 4c, which is formed in the cylindrical portion 4a. Further, a driving pin 3c provided on the ceiling plate 3b of the rotor member 3 in a protruding manner is caught in a hub hole of the steering wheel 11. When the steering wheel 11 is rotated clockwise or anticlockwise, the rotor member 3 is rotated in the same direction by the rotating force of the wheel 11. Thus, the flexible cable 5 is wound or unwound in the annular space. At that time, the rotor member 3 and the slip-off preventing member 4 snap-connected thereto integrally rotate. The rotation of the slip-off preventing member 4 causes the cancel cam 4c and the canceling lever 10 of the canceling mechanism to operate. Consequently, in the case that a winker operation is performed by moving the operation lever 9 to a left-hand or right-hand position, as the steering wheel 11 is rotated and returned to a neutral position, the operation lever 9 is automatically returned to a center position.
Meanwhile, in the aforementioned conventional rotary connector, the cancel cam 4c is formed on the slip-off preventing member 4 snap-connected to the rotor member 3. It is usually necessary to provide some clearance in this snap-connected portion. This clearance causes backlash in the rotational direction (or in the radial direction) between the rotor member 3 and the slip-off preventing member 4 and also causes deviation in the rotational direction between the steering wheel 11 and the cancel cam 4c. Consequently, the conventional rotary connector has a drawback in that the canceling lever 10 does not operate accurately.
Moreover, because the cancel cam 4c is formed on the slip-off preventing member 4, the stator member 2 of the rotary connector 1 is fixed to the top surface of the casing 7 of the combination switch 6. It is thus necessary to provide a space, in which the rotary connector 1 is placed, between the steering wheel 11 and the combination switch 6. Consequently, the conventional rotary connector has another drawback in that the height dimension of the rotary connector 1 is seriously limited.